Automatic mass-flow sensor calibration for a yield monitor

ABSTRACT

A system and method is provided for remotely and automatically calibrating a mass-flow sensor in a yield monitor of a combine. The invention uses a wireless communication device installed on a combine and a remote wireless communication device installed on a grain carrier or truck carrier. Once an actual weight is obtained, calibration information is sent to the combine to calibrate the mass-flow sensor.

This application is a division of U.S. application Ser. No. 10/909,241filed Jul. 30, 2004 now U.S. Pat. No. 7,073,314; which is a division ofU.S. application Ser. No. 10/246,217 filed Sep. 18, 2002, now U.S. Pat.No. 6,820,459.

FIELD OF THE INVENTION

This invention relates to the field of yield monitoring. In particular,this invention is drawn to an automated wireless calibration technique.

BACKGROUND OF THE INVENTION

Combines commonly include yield monitors to determine desired propertiesof agricultural products as they are harvested. A typical yield monitorincludes sensors, such as a mass-flow sensor and a moisture sensor. Toobtain an accurate measurement of yield, the mass-flow sensor andmoisture sensor must be periodically calibrated. The procedure forcalibrating a mass-flow sensor normally involves harvesting grain,filling a grain cart, truck, or semi trailer, and comparing the measuredweight with a more accurate weight obtained from a grain cart with aweighing system or from a certified truck scale.

One problem with prior art calibration techniques is that when a truckor trailer travels to a remote scale, a significant amount of time mayelapse between the start of the calibration procedure and the end. Inaddition, a farmer may hesitate to stop harvesting while waiting toreceive the actual weights from the calibration load. During the timethat the trucks are away from the field, the calibration factor for themass-flow sensor could be off significantly. Grain carts that areequipped with a weighing system can be used to more easily and quicklymanually calibrate a mass-flow sensor. However, many grain carts are notequipped with a weighing system because they do not add significantvalue to the system.

In either case, the actual calibration load weight requires a manualentry into a display device (such as a GreenStar Display device). Themanual entry of calibration information takes time for the operator. Inaddition, if the operator does not calibrate frequently, the accuracy ofthe mass-flow sensor can decrease since the load is based on a largeraverage and not the latest field conditions. Typically, it is consideredtoo time-consuming to manually update the calibration factor after everyload.

SUMMARY OF THE INVENTION

A method of the invention is provided for calibrating a mass-flow sensoron a yield monitor of a combine, comprising the steps of: harvestinggrain using the combine; transferring the harvested grain to a locationwhere its actual weight can be determined; providing a wirelesscommunication device on the combine; transmitting information relatingto the actual weight of the harvested grain to the wirelesscommunication device on the combine; and calibrating the mass-flowsensor using the information.

Another embodiment of the invention provides a system for calibrating amass-flow sensor on a yield monitor of a combine, comprising the stepsof: a first wireless transceiver operatively connected to the yieldmonitor; and a second wireless transceiver operatively connected to agrain carrier for transmitting calibration information to the firstwireless transceiver.

Another embodiment of the invention provides a method of remotelycalibrating a sensor on a combine, comprising the steps of: providing awireless communication device on the combine; providing a remotewireless communication device; after harvesting an agricultural product,removing the harvested agricultural product from the combine;determining certain properties of the harvested agricultural product;transmitting information from the remote wireless communication deviceto the wireless communication device on the combine; and using theinformation to calibrate the sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and notlimitation in the figures of the accompanying drawings, in which likereferences indicate similar elements and in which:

FIG. 1 is a block diagram of a combine and a grain carrier using thepresent invention.

FIG. 2 is a flowchart illustrating a procedure for establishing awireless connection between a combine and a grain carrier.

FIG. 3 is a flowchart illustrating a wireless connection start-upprocedure.

FIG. 4 is a flowchart illustrating a procedure for maintaining awireless connection.

FIG. 5 is a flowchart of a combine unloading auger status changeprocedure.

FIG. 6 is a flowchart illustrating the process of calibrating a load.

FIGS. 7-11 pertain primarily to the calibration of the combine.

FIG. 7 is a flowchart for establishing a wireless connection in regardto the combine.

Specifically, FIG. 8 is a block diagram showing the wireless startupprocedure for the combine.

FIG. 9 is a flowchart showing the procedure for maintaining connection.

FIG. 10 is a flowchart showing the unloading auger status change for thecombine.

FIG. 11 is a flowchart showing the procedure for weighing the last loadon the combine.

DESCRIPTION OF THE INVENTION

The present invention provides a system and method for remotely andautomatically calibrating sensors, such as the mass-flow sensor, in ayield monitor of a combine. The invention uses a wireless communicationdevice installed on a combine and a remote wireless communicationdevice. The remote wireless communication device can be installed on agrain cart having an electronic weighing system, on a truck or semitrailer, or installed on any other device having access to desiredinformation.

While harvesting, the yield monitor takes information from the mass-flowsensor and generates an estimation of the weight of the harvestedproduct. Once the actual weight of the harvested product is known(either from the grain cart weighing system, or from a truck scale,etc.), calibration information relating to a particular load can betransmitted to the combine, where it can be used to re-calibrate themass-flow sensor. The calibration information may be comprised of acalibration factor related to the actual and estimated weights.Alternatively, the calibration information may simply be comprised ofinformation relating to the actual weight. In that case, a calibrationfactor is calculated on the combine. The new calibration factor, basedon the transmitted information, can be applied to previously harvestedload grain to scale the yield and to get a more accurate representationof the yield throughout the field during all harvest conditions.

In the case where the remote wireless communication device is installedon a truck or semi trailer, the actual weight information can be storedand transmitted to the combine later (e.g., when the truck or trailer isin closer proximity to the combine).

The automatic calibration procedure of the present invention facilitatescontinual calibration updates on a load by load basis, which results ina reduction of yield monitoring errors. In addition, the measured yieldof harvested loads are more accurate because they represent currentharvest conditions, as opposed to an average condition when the lastcalibration was performed.

Following is a description of one example of an implementation of thepresent invention. FIG. 1 is a block diagram of a combine 10 and a graincarrier 12. The grain carrier 12 may be comprised of a grain cart,truck, semi trailer, or any other suitable grain carrying device. Thecombine 10 includes a mass-flow sensor 14 which is connected to a yieldmonitor 16. As described above, the yield monitor 16 is capable ofproviding an estimated weight of the harvested grain based oninformation from the mass-flow sensor 14. Note that various othersensors and components are not shown for purposes of clarity. The yieldmonitor 16 is connected to a wireless communication device transceiver18, which is connected to an antenna 20.

The grain carrier 12 has a wireless transceiver 24, which is connectedto an antenna 26. The wireless transceiver 24 is connected to acalibration processor 28 which generates calibration information basedon the actual weight of grain in the grain carrier 12. The combinewireless transceiver 18 is capable of exchanging information with thegrain carrier wireless communication device transceiver 24.

When the combine 10 harvests a load of grain, the yield monitor 16estimates the weight of the load of grain based on information from themass-flow sensor 14. After harvested grain is transferred to the graincarrier 12, the grain is weighed, either by a truck scale or on thegrain carrier 12 if the grain carrier has load weighing capabilities.The actual weight of the grain is used by the calibration processor 28to generate calibration information which is transmitted back to thecombine 10 for use by the yield monitor 16 to calibrate the mass-flowsensor 14. The calibration information may include a calibration factorrelating to the actual weight, an old calibration factor, and the weightestimated by the yield monitor. Alternately, the calibration informationmay just include the actual weight.

FIGS. 2-5 are a detailed flow charts illustrating one example of theoperation of the present invention. Generally, in FIGS. 2-5, processesperformed on the combine are shown to the left, and processes performedin the grain carrier are shown to the right. The processes performed atthe combine and at the grain carrier are executed in parallel. Pleasenote that various functions can take place at either the combine or thegrain carrier. FIGS. 2-5 simply show one example of the invention.

FIG. 2 is a flowchart illustrating the establishment of a wirelessconnection between a combine and a grain carrier. At the combine, theprocess starts with step 30 where the process retrieves the currentcalibration factor. In addition, a wireless connection variable is setto FALSE at step 32. At the grain carrier, the process starts with step34 where an empty combine database is created. Note that the combinedatabase may include information for one, or multiple combines. Inaddition, a wireless connection variable is set to FALSE at step 36. Atstep 37, the wireless transceiver of the combine transmits a CONNECTmessage. If, at step 38, it is determined that no message has beenreceived from the grain carrier, the process loops back to step 32. Thisloop will continue until a reply message is received from the graincarrier.

At step 39, the grain carrier receives the CONNECT message from thewireless transceiver of the combine and the process proceeds to step 40.At step 40, the process asks whether the distance between the graincarrier and combine is less than a maximum desired distance (variableMAX_DIST) and whether the heading difference is less than a maximumdesired difference (variable MAX_DIFF). If so, the process proceeds tostep 42 where an acknowledgement signal is transmitted, and received (atstep 44) by the combine. If not, then the process proceeds to step 43,where an attempt is made to calibrate the last combine load (see FIG.6). At this point, a wireless connection has been established betweenthe combine in the grain carrier. At both the combine and grain carrier,a wireless connection variable is set to TRUE (steps 46 and 48).

Once a wireless connection is established, a wireless connectionstart-up procedure is started. FIG. 3 is a flow chart of the wirelessconnection start-up procedure. At step 50, the combine transmits itslatest calibration factor. At step 52, the grain carrier receives thecalibration factor from the combine. At step 54, the grain carriertransmits an acknowledgement signal, which is received by the combine atstep 56. After transmitting the acknowledgement, the receivedinformation is stored in the combine database at step 58. Next, at step60, the process asks whether the previous combine load calibrationinformation is available. If not, the process proceeds to step 82,described below. If previous combine load calibration information isavailable, the process proceeds to step 62 where the previous loadcalibration factor is transmitted to the combine. At step 64, thecombine receives the previous load calibration factor. In response, thecombine transmits an acknowledgement signal at step 66. The graincarrier receives the acknowledgement at step 68. At the combine, theprocess proceeds to step 70 where the received calibration factor issaved and associated with a load number. Next, at step 72, the processasks whether the last load calibration factor was received. If so, theprocess proceeds to step 74 where the calibration factor is set to thelast load calibration factor. At the grain carrier, the process proceedsto step 76 where the process asks whether the last load was calibrated.If so, the process proceeds to step 82. If not, the process proceeds tostep 78 where the system informs the operator to stop and perform acalibration.

After the wireless connection start-up procedure described above hasbeen completed, a process begins which maintains the connection. FIG. 4is a flowchart of a procedure to maintain the connection. At step 80 ofFIG. 4, the process asks whether the time elapsed since the lastreceived signal is greater than a threshold value (e.g., 7 seconds). Ifso, it is determined that the connection has been lost and the processgoes back to step 32 of FIG. 2. At step 82, the grain carrier attemptsto calibrate the load. The process of calibrating a load is describedbelow and illustrated in FIG. 6. Next, at step 84 the process askswhether the time elapsed since the last received signal is greater thana threshold value (e.g., 7 seconds). If so, it is determined that theconnection has been lost and the process goes back to step 36 of FIG. 2.If a connection is maintained, the process at the combine goes through aloop until the connection is lost or the status of the unloading augerhas changed. At step 86, the process asks whether the unloading augerstatus has changed. If so, the process proceeds to step 100 in FIG. 5.If not, the process asks at step 88 whether the time elapsed since thelast transmission is greater than a threshold value (e.g., 2 seconds).If not, the process proceeds back to step 80. If so, the processproceeds to step 90 and a CHECK_CONNECTION signal is transmitted. At thegrain carrier, the process proceeds to step 92 and asks whether amessage has been received. If not, the process goes back to step 82. Ifthe CHECK_CONNECTION is received at step 94, an acknowledgment istransmitted at step 96 and received by the combine at step 98. Theprocess at the grain carrier then proceeds back to step 82.

FIG. 5 is a flowchart of the combine unloading auger status changeprocedure. If, back at step 86, it was determined that the status of theunloading auger changed, the process illustrated in FIG. 5 is performed.The process illustrated in FIG. 5 begins with step 100 where the processasks whether the unloading auger is engaged. If the unloading auger isengaged (i.e., the combine has just begun unloading grain), the processproceeds to step 102 where the combine transmits an auger engagedsignal. At step 104, the grain carrier receives the auger engaged signaland transmits an acknowledgement signal (step 106). At step 108, thecombine receives the acknowledgement signal and the process proceedsback to steps 80 and 82 shown in FIG. 4. If, at step 100, the auger isnot engaged (i.e., the combine has just finished unloading grain) theprocess proceeds to step 110 where the combine transmits an augerdisengaged signal. In addition, at step 112, the combine transmits anaccumulated weight signal, relating to the estimated weight generated bythe yield monitor. At steps 114 and 116, the grain carrier receives theauger disengaged signal and the accumulated weight signal. At step 118,the grain carrier transmits an acknowledgement signal which is receivedby the combine at step 120. At the combine, the process proceeds to step122 where the combine accumulated weight variable is reset. At the graincarrier, the process proceeds to step 124 where the combine load data isstored. Next, at step 126, an attempt is made to calibrate the load (seeFIG. 6). At step 128 the grain carrier transmits an acknowledgementsignal, which is received by the combine at step 130. Next, the processproceeds back to steps 80 and 82 of FIG. 4.

FIG. 6 is a flowchart illustrating the process of attempting tocalibrate the last load. Note that this process may be executed beforeor after a wireless connection is established. The process begins atstep 140 where the process asks whether the grain carrier is stationary.If not, the process ends. If the grain carrier is stationary, theprocess proceeds to step 142 where the current cart weight is read. Inthe case of a grain cart having weighing capabilities, the grain cartweighing system can provide the weight. In the case of a grain carrierbeing weighed on a truck scale, the weight is provided by the scale.Next, at step 144, the accurate weight variable is set to TRUE. At step146, the process asks whether a prior weight is stored. If not, theprocess ends. If a prior weight is stored, the process proceeds to step148 where the actual weight variable is set equal to the final weightminus the initial weight (i.e., the actual weight of the grain iscalculated since the measured weights include the weight of the graincarrier). At step 150, the process asks whether the last combine loadwas calibrated. If so, the process ends. If the last combine load wasnot calibrated, the process proceeds to step 152 where a new calibrationfactor is calculated. The new calibration factor is set equal to the oldcalibration factor times the ratio of the estimated weight from thecombine to the actual weight calculated above. After step 152, theprocess ends.

In the description below, the invention will be described in the contextof a combine grain harvester, although it to is understood that theinvention may be used with any type of agricultural product.

FIGS. 7-11 are flow charts illustrating an example of the operation ofthe present invention relating primarily to the calibration of acombine.

FIG. 7 is a flowchart illustrating the establishment of a wirelessconnection between a combine and a grain carrier. At the combine, theprocess starts with step 160 where a wireless connection variable is setto FALSE. At the grain carrier, the process starts with step 162 wherean empty combine load database is created. In addition, a wirelessconnection variable is set to FALSE at step 164. At step 166, thewireless transceiver of the combine transmits a CONNECT message. If, atstep 168, it is determined that no message has been received from thegrain carrier, the process loops back to step 160. This loop willcontinue until a reply message is received from the grain carrier.

At step 170, the grain carrier receives the CONNECT message from thewireless transceiver of the combine and the process proceeds to step172. At step 172, the process asks whether the distance between thegrain carrier and combine is less than a maximum desired distance(variable MAX_DIST), whether the heading difference is less than amaximum desired difference (variable MAX_DIFF), and if it is on the leftside of the combine. If so, the process proceeds to step 174 where anacknowledgement signal is transmitted, and received (at step 168) by thecombine. If not, then the process proceeds to step 176, where an attemptis made to weigh the last combine load. At this point, a wirelessconnection has been established between the combine in the graincarrier. At both the combine and grain carrier, a wireless connectionvariable is set to TRUE (steps 178 and 180).

Once a wireless connection is established, a wireless connectionstart-up procedure is started. FIG. 8 is a flow chart of the wirelessconnection start-up procedure for the combine. At step 182, the processasks whether the combine load weight is available. If not, the processproceeds to step 206 (FIG. 9), described below. If the combine loadweight is available, the process proceeds to step 184 where the actualload weight is transmitted to the combine. At step 186, the combinereceives the actual load weight. In response, the combine transmits anacknowledgement signal at step 188. The grain carrier receives theacknowledgement at step 190. At the combine, the process proceeds tostep 192 where the actual load weight is transmitted for use in acombine yield mapping process. At step 194, a routine is executed tocalculate a new load calibration factor, based on the actual loadweight. Next, at step 196, the process asks whether the last load wasreceived. If so, the process proceeds to step 198 where the calibrationfactor is set to the last load calibration. At the grain carrier, theprocess proceeds to step 200 where the process asks whether the lastload was weighed. If so, the process proceeds to step 206 (FIG. 9). Ifnot, the process proceeds to step 202 where the system informs theoperator to stop and weigh the load.

After the wireless connection start-up procedure described above hasbeen completed, a process begins which maintains the connection. FIG. 9is a flowchart of a procedure to maintain the connection. At step 204,the process asks whether the time elapsed since the last received signalis greater than a threshold value (e.g., 7 seconds). If so, it isdetermined that the connection has been lost and the process goes backto step 160 of FIG. 7. At step 206, the grain carrier attempts to weighthe load. Next, at step 208 the process asks whether the time elapsedsince the last received signal is greater than a threshold value (e.g.,7 seconds). If so, it is determined that the connection has been lostand the process goes back to step 164 of FIG. 7. If a connection ismaintained, the process at the combine goes through a loop until theconnection is lost or the status of the unloading auger has changed. Atstep 210, the process asks whether the unloading auger status haschanged. If so, the processors the process proceeds to step 224 in FIG.10. If not, the process asks at step 212 whether the time elapsed sincethe last transmission is greater than a threshold value (e.g., 2seconds). If not, the process proceeds back to step 204. If so, theprocess proceeds to step 214 and a CHECK_CONNECTION signal istransmitted. At the grain carrier, the process proceeds to step 216 andasks whether a message has been received. If not, the process goes backto step 206. If the CHECK_CONNECTION is received at step 218, anacknowledgment is transmitted at step 220 and received by the combine atstep 222. The process at the grain carrier then proceeds back to step206.

FIG. 10 is a flowchart of the combine unloading auger status changeprocedure. If, back at step 210, it was determined that the status ofthe unloading auger changed, the process illustrated in FIG. 10 isperformed. The process illustrated in FIG. 10 begins with step 224 wherethe process asks whether the unloading auger is engaged. If theunloading auger is engaged (i.e., the combine has just begun unloadinggrain), the process proceeds to step 226 where the combine transmits anauger engaged signal. At step 228, the grain carrier receives the augerengaged signal and transmits an acknowledgment signal (step 230). Atstep 232, the combine receives the acknowledgment signal and the processproceeds back to steps 204 and 206 shown in FIG. 9. If, at step 224, theauger is not engaged (i.e., the combine has just finished unloadinggrain) the process proceeds to steps 234 and 236 where the combinetransmits an auger disengaged signal and the combine accumulated weightvariable is reset. At step 238, the grain carrier receives the augerdisengaged signal, and stores the combine load number at step 240. Atstep 242 the grain carrier transmits an acknowledgment signal, which isreceived by the combine at step 244. Next, the process proceeds to steps204 and 206 of FIG. 9, where an attempt is made to weigh the load. Atstep 246, the process asks whether the gain cart is empty. If so, theprocess proceeds to step 248 where the load is saved in the database. Ifnot, the process proceeds to step 250 where the load is marked as“Unable to be Calibrated”. The process then proceeds to the combineyield mapping routine.

FIG. 11 is a flowchart illustrating the process of weighing the lastload on the combine. The process begins at step 252 where the processasks whether the grain carrier is stationary. If not, the process ends.If the grain carrier is stationary, the process proceeds to step 254where the current cart weight is read. Next, at step 256, the accurateweight variable is set to TRUE. At step 258, the process asks whether aprior weight is stored. If not, the process ends. If a prior weight isstored, the process proceeds to step 260 where the actual weightvariable is set equal to the final weight minus the initial weight(i.e., the actual weight of the grain is calculated since the measuredweights include the weight of the grain carrier). At step 262, theactual weight with the combine load number is stored and the processends.

While the present invention was described in the context of a mass-flowsensor on a combine, the invention could also be used in other ways. Forexample, the invention could be used to calibrate other sensors such asa moisture sensor. In addition, the calibration information could comefrom other sources. For example, an elevator could send calibrationinformation to combines after weighing grain that is brought to theelevator. Other embodiments and alternatives are also possible.

In the preceding detailed description, the invention is described withreference to specific exemplary embodiments thereof. Variousmodifications and changes may be made thereto without departing from thebroader spirit and scope of the invention as set forth in the claims.The specification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense.

1. A system for calibrating a mass-flow sensor of a combine, the systemcomprising: a yield monitor associated with the mass flow sensor; afirst wireless transceiver operatively connected to the yield monitor; asecond wireless transceiver on a grain carrier for transmittingcalibration information relating to the actual weight to the firstwireless transceiver, the second wireless transceiver arranged fortransmitting an acknowledgement signal to the first wireless transceiverregarding a distance between the grain carrier and the combine and aheading difference between the grain carrier and the combine, whereinthe mass-flow sensor is calibrated for a load of the combine if thedistance is less than a maximum desired distance and if the headingdifference between the grain carrier and the combine is less than amaximum desired difference.
 2. The system of claim 1, wherein grainharvested by the combine is transferred to the grain carrier.
 3. Thesystem of claim 2, wherein the calibration information includesinformation relating to the weight of the grain in the grain carrier. 4.The system of claim 1 wherein the grain carrier further comprises: acalibration processor for generating calibration information fortransmission from the second wireless transceiver to the first wirelesstransceiver for calibrating the mass-flow sensor.
 5. The system of claim1 wherein the load of the combine is calibrated as a last load if thedistance is greater than the maximum desired distance.
 6. The system ofclaim 5 wherein the calibration of the last load is accomplished inaccordance with the following equation: NewCalib=OldCalib *(EstimatedWeight/Actual Weight); wherein NewCalib means a new calibration of themass-flow sensor, OldCalib means an old or previous calibration of themass-flow sensor, Estimated Weight means an estimated weight of theload, and Actual Weight means an actual weight of the load.
 7. Thesystem of claim 1 wherein the load is calibrated as a current load ifthe distance is less than the maximum desired distance, if the headingdifference is less than a maximum desired heading difference and if arelative position between the grain carrier and the combine is on a loadtransferring side of the combine.
 8. The system according to claim 1further comprising: a weighing system, associated with the graincarrier, for determining an actual weight of a grain carrier load of anagricultural product carried by the grain carrier.
 9. A system forcalibrating the mass flow sensor on a combine comprising: a yieldmonitor coupled to a mass flow sensor on the combine; a first wirelesscommunications device on the combine and capable of communication withthe yield monitor that calibrates the mass flow sensor; a secondwireless communications device capable of communication with the firstwireless communications device on the combine, the second wirelesscommunications device adapted to transmit information relating to anactual weight of the harvested grain for calibration of the mass flowsensor if a distance between the combine and the vehicle is less than amaximum desired distance and if a heading difference between the vehicleand the combine is less than a maximum desired difference.
 10. Thesystem of claim 9 wherein the second communications device comprises aremote wireless communications device on a grain carrier as the vehicle.11. The system of claim 9 wherein the second communications devicecomprises a remote wireless communications device on a truck as thevehicle.
 12. The system according to claim 9 further comprising: aweighing system, associated with a vehicle, for determining an actualweight of a vehicle load of an agricultural product carried by thevehicle.